The invention relates to an assembly and related method for the removal of a stent from a body vessel.
Methodology of the treatment of vascular afflictions by the introduction of a so-called "stent" into the affected (weakened or locally clogged) body vessel is being developed continuously. A stent is (see for example European patent application 0 452 219) a hollow, often cylindrical, element which is introduced into the body vessel at the desired location by means of a suitable catheter system and supports the wall of the vessel locally.
Afflictions of blood vessels, esophagus, gall ducts and the like can be treated in this manner.
Using the current state of the art, once such a stent expands within the body, it can only be removed by a conventional surgical operation which involves cutting through the patients skin and tissues. This is, of course, especially traumatic and stressful for a patient.
There exists, therefore, a great need for an assembly and method with which it is possible to remove an introduced and deployed stent without requiring operational intervention. The present invention aims to fulfil this need.
In this regard, the invention provides an assembly to achieve the function as described above which is characterized by an expandable element or balloon, connected to a pulling device, the outer surface of which is covered with an adhesive medium and which, when the expandable element or balloon is positioned inside the stent, is expanded and lies with its outer surface against the inner surface of the stent, and brings about an attachment between this outer surface and the inner surface of the stent.
After this attachment has been achieved, the expandable element, with the stent attached to it, can be removed by pulling back the complete unit out of the vessel. It is clear that such an operation is not very stressful for the patient, no more than a normal catheterization procedure.
The expandable element can be hollow and be brought into its expanded state by filling with a medium under pressure. In a suitable embodiment, the expandable element is formed by the balloon of a catheter balloon assembly for percutaneous angioplasty.
The adhesive medium can comprise a pressure-sensitive, or an adhesive which is cured by the action of UV radiation. In this latter case, the assembly will be provided with a radiation guide extending into or close to the balloon. The adhesive medium can also comprise a fast-acting adhesive layer.
The whole expandable element can be protected by or slidably enclosed within a protecting sleeve which is connected to a draw wire guided along the catheter or extending alongside the catheter.
When the expandable element is manipulated into engagement with the stent, a very good attachment will occur between the outer wall of the expandable element and the inner wall of the stent. This has the result that, when the thin expandable element contracts so as to reduce its outer diameter, the stent attached to its outer surface--when the stent is made of compliant material--will likewise contract to a smaller outer diameter and can therefore be more easily removed from the body vessel without requiring fully invasive surgery.